transaction when through on expired card

I reported a transaction that went off on the 7th of March 2-26 on a card that has already expired at the end of Jan 2026. This was a renewal of a free 30 day trail that I was not aware off, I have been in contact with the supplier and is also asking for a refund from their side, but in the mean time I send all the info requested and keep on getting the same mail requesting the same thing, my biggest question that no one is answering, is how could a transaction happen on an expired card